目录摘要 (I)Abstract (II)1 污水处理概述 (1)1.1本课题研究的意义 (1)1.2污水处理厂工艺流程 (3)1.3污泥脱水过程中加药系统的国内外现状 (3)1.4本文的主要研究内容及目的 (5)2 全自动加药系统的工艺及控制要求 (7)2.1污泥的产生 (7)2.2污泥的处理处置 (9)2.3絮凝剂的使用 (9)2.4全自动加药系统的工艺流程 (10)2.5控制要求 (11)3 全自动加药系统主要设备的设计 (13)3.1絮凝剂浸润系统的总体构成 (13)3.2搅拌轴设计[1] (14)3.2.1强度计算 (14)3.2.2搅拌轴刚度校核 (15)3.2.3临界转速校核 (16)3.3搅拌器的设计 (17)3.3.1特性与结构 (17)3.3.2确定搅拌器功率N (17)3.3.3强度计算 (19)3.4 电动机功率 (20)3.5搅拌罐的设计 (21)3.6 搅拌附件的设计 (22)3.7计量加药装置的设计 (23)3.7.1计量加药装置的结构 (23)3.7.2螺旋设计[2] (23)3.8加热料仓设计 (27)3.9给水加料系统 (28)4 自动化控制系统的设计 (30)4.1工作过程 (30)4.2设计方案 (33)4.2.1系统硬件设计 (33)4.2.2系统PLC的选择 (33)4.3主电路电器组件的选择 (33)4.4操作面板的布置 (34)4.5系统软件设计 (35)4.5.1 PLC的1/O分配表 (35)4.5.2电气控制设计 (35)5 总结与展望 (40)5.1设备部分 (40)5.2控制系统 (41)5.3总结 (41)致谢 (42)参考文献 (43)摘要在水资源异常宝贵的今天，污水处理及回用尤成为当今世界性的重大问题，在目前的各种污水处理方案中，絮凝剂、助凝剂的使用是其中必不可少的一种辅助措施，这样用于溶解及投加这种物质的设备在污水处理工程中的应用就非常的普遍。
在过去传统的污水处理中，这种投药装置多采用人工控制。
这种控制存在的问题是，药剂用量的不准确，控制缺少及时性等，这就直接影响到水质的处理结果，而且对于几万元一吨造价昂贵的高分子絮凝剂来说，长期非科学性的用量造成的资金损失也是非常可观的。
本文根据污水处理工程中的实际应用，提供一种全自动加药系统。
对在搅拌过程中容易产生振动和偏摆的搅拌轴和搅拌浆叶，用有限元法进行子分析，确定了搅拌轴的临界转速，校核了搅拌桨叶的强度；并通过分析核算给出整个系统中其它主要设备的设计说明。
本系统的主要优点为：1)溶药罐和储药罐均设有液位计，罐内液位、各环节工作信息传送至PLC控制系统，从而使加药系统全自动运行，药液浓度恒定，投加准确；2)储药罐的容积设计合理，既能满足溶药罐每2个小时为周期的排药储存，又能满足用药计量泵连续向絮凝器供药的流量要求。
3)通过搅拌机2个小时的搅拌，形成了独特的药剂浸润技术，避免了絮凝剂的溶解不均；具有加热性能的料仓结构，避免了干粉絮凝剂受潮结块；4)利用可调转速的螺旋供料器保证可调的加药量，根据现场情况确定有效的药液浓度；5)控制系统先进，设备运行连续、平稳安全可靠。
通过本文的论述旨在找到一种实用价值更高，应用前景更广阔的产品，从而达到环境效益与经济效益的统一。
关键词：污水处理全自动加药装置；PLC控制；絮凝剂搅拌AbstractNowadays water resources are becoming more and more precious. As a result,sewage disposal and recycling become major issues worldwide. Among varioussewage disposal techniques, the use of flocculating agent and coagulation-supporting agent is an auxiliary measure that is absolutely necessary. Thus, the use of the equipment for dissolving and feeding such agent in the process of sewage disposal is quite common.For the old-fashioned and traditional sewage disposal techniques, mostly their agent-feeding devices are controlled manually. With such controlling method certain problems exist：the inaccuracy of the quantity of the agent, lack of timely response etc. Those problems directly affect the quality of sewage disposal. Moreover, as the price of macromolecule flocculating agent is extremely high, the financial losses caused by the inaccuracy of the quantity of the agent to be added are highly considerable.According to the practical operation in sewage disposal, this thesis provides a completely automatic agent-feeding system. The mixing axle and the oar-shaped vane are apt to vibrate and sway during the mixing process. In order to solve this problem, the finity block was used to determine the critical speed of the mixing axle, and the strength of the oar-shaped vane was examined. Through analysis the design specifications of the other main equipment of the whole system were given.The main strong points of this system：1) Both the dissolution tank and the storage tank are equipped with level indicators. The liquid level in the tanks and the operation information of various parts are transmitted to PLC controlling system. Thus, the operation is completely automatic, the density of the agent is constant, the quantity of the agent is accurate；2）The design of the storage tank's volume is reasonable. It can meet both the requirement for the dissolution tank to let off the agent every two hours, and the flow requirement for the measuring pump to feed the flocculating device continuously.3) After two hours' mixing in the mixing machine, a unique technique of agent soakage is achieved. The uneven dissolution of the flocculating agent is avoided. The heating depository can prevent the dry flocculating agent from agglomeration due to damp.4) The rotate speed of the spiral feeder is adjustable. Hence, the quantity of the agent can be adjusted according to the worksite conditions, the effective density of the agent is ensured；5）The controlling system is advanced, the operation is continuous, stable, safe and reliable；The aim of this thesis is to find a product whose practical value is higher and whose application is wider. Ultimately, both environmental and economic benefits can be obtained.Key Words：sewage disposal completely automatic agent-feeding device PLC controlling flocculating agent finity block mixing1 污水处理概述1.1本课题研究的意义世界任何国家的经济发展，都会推向社会进步、促进工农业生产能力得到提高，使人民生活得到进一步改善，但是也随之带来不同程序的环境污染。
污水也是造成环境污染的来源之一。
这个污染源的出现引起了世界各国政府的关注，治理水污染环境的课题被列入世界环保组织的工作日程。
中国政府历来重视环保治理工作，敬爱的周恩来总理提出了“全国规划，合理布局，综合利用，化害为利，领先群众，大家动手，保护环境，造福人民”32字方针，历届政府提出根治海河、三河三湖的治理的要求。